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Acetyl-L-Carnitine

Uses

Acetyl-L-carnitine is similar in form to the amino acid L-carnitine and also has some similar functions, such as being
involved in the metabolism of food into energy. The acetyl group that is part of acetyl-L-carnitine contributes to the production of the neurotransmitter acetylcholine, which is required for mental function.

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for

Why

3 Stars

Age-Related Cognitive Decline

1,500 mg daily

Several clinical trials suggest that this supplement delays onset of ARCD and improves overall cognitive function in the elderly

Several clinical trials suggest that acetyl-L-carnitine delays onset of ARCD and improves overall cognitive function in the elderly. In a controlled clinical trial, acetyl-L-carnitine was given to elderly people with mild cognitive impairment. After 45 days of acetyl-L-carnitine supplementation at 1,500 mg per day, significant improvements in cognitive function (especially memory) were observed.1 Another large trial of acetyl-L-carnitine for mild cognitive impairment in the elderly found that 1,500 mg per day for 90 days significantly improved memory, mood, and responses to stress. The favorable effects persisted at least 30 days after treatment was discontinued.2 Controlled3, 4, 5 and uncontrolled6 clinical trials on acetyl-L-carnitine corroborate these findings.

In a double-blind study of people with diabetic neuropathy, supplementing with acetyl-L-carnitine was significantly more effective than a placebo in improving subjective symptoms of neuropathy and objective measures of nerve function.7 People who received 1,000 mg of acetyl-L-carnitine three times per day tended to fare better than those who received 500 mg three times per day.

2 Stars

Alzheimer’s Disease

1 gram taken three times per day

Short-term studies have found that people with Alzheimer’s disease who supplement with acetyl-L-carnitine experience improved memory, enhanced overall performance, and delayed disease progression.

Several clinical trials have found that acetyl-L-carnitine supplementation delays the progression of Alzheimer’s disease,8 improves memory,9, 10, 11 and enhances overall performance in some people with Alzheimer’s disease.12, 13 However, in one double-blind trial, people who received acetyl-L-carnitine (1 gram three times per day) deteriorated at the same rate as those given a placebo.14 Overall, however, most short-term studies have shown clinical benefits, and most long-term studies (one year) have shown a reduction in the rate of deterioration.15 A typical supplemental amount is 1 gram taken three times per day.

2 Stars

Depression

Refer to label instructions

Acetyl-L-carnitine has been shown in several studies to significantly reduce depression symptoms in seniors.

Acetyl-L-carnitine may be effective for depression experienced by the elderly. A preliminary trial found that acetyl-L-carnitine supplementation was effective at relieving depression in a group of elderly people, particularly those showing more serious clinical symptoms.16 These results were confirmed in another similar clinical trial.17 In that trial, participants received either 500 mg three times a day of acetyl-L-carnitine or a matching placebo. Those receiving acetyl-L-carnitine experienced significantly reduced symptoms of depression compared to those receiving placebo. At least two other clinical studies of acetyl-L-carnitine for depression in the elderly have reported similar results.18, 19 The amount typically used is 500 mg three times daily, although one trial used twice that amount.

2 Stars

Down’s Syndrome

500 mg three times per day

Acetyl-L-carnitine appears to improve visual memory and attention in people with Down’s Syndrome.

Acetyl-L-carnitine is a compound that occurs naturally in the brain and plays a role in the normal functioning of the nervous system. In a preliminary trial, patients with Down’s syndrome were given 500 mg of L-acetyl-carnitine three times daily for 90 days and were observed to improve in visual memory and attention. Similar improvement was not seen in untreated patients, nor in patients with mental deficiency unrelated to Down’s syndrome who were also given L-acetyl-carnitine.20 More research into the effects of L-acetyl-carnitine in people with Down’s syndrome is needed.

2 Stars

Erectile Dysfunction (L-Carnitine)

2 grams of each daily

In one study, supplementing with the combination of propionyl-L-carnitine (a form of L-carnitine) and acetyl-L-carnitine significantly improved erectile function in elderly men.

In a double-blind study, supplementing with the combination of propionyl-L-carnitine (a form of L-carnitine) and acetyl-L-carnitine (2 grams of each per day) for six months significantly improved erectile function in elderly men with erectile dysfunction associated with low testosterone levels. Propionyl-L-carnitine and acetyl-L-carnitine were significantly more effective than testosterone treatment.21

2 Stars

Fibromyalgia

1,500 mg daily for ten weeks

Supplementing with acetyl-L-carnitine may improve musculoskeletal pain, depression, and general health in people with fibromyalgia.

In a double-blind trial, supplementation with acetyl-L-carnitine in the amount of 1,500 mg per day for ten weeks was significantly more effective than a placebo in improving musculoskeletal pain, depression, and general health in people with fibromyalgia.22

2 Stars

Liver Cirrhosis

2 grams twice a day for 3 months

A double-blind trial suggests that supplementing with acety-l-carnitine may improve mental and neurological function in people whose cirrhosis has impaired function.

In double-blind trials, supplementing with acety-L-carnitine (2 grams twice a day for three months) improved fatigue and various measures of mental and neurological function in people with impaired function (minimal hepatic encephalopathy) due to cirrhosis.23, 24

2 Stars

Macular Degeneration (Coenzyme Q10, Fish Oil)

Follow label directions

In one study, supplementing with a proprietary blend of acetyl-L-carnitine, fish oil, and coenzyme Q10 improved visual function in people with macular degeneration.

In a double-blind study, supplementation with a proprietary blend of acetyl-L-carnitine, omega-3 fatty acids from fish oil, and coenzyme Q10 for 12 months resulted in an improvement in both visual function and in objective findings on eye examination (a decrease in the drusen-covered area on the retina).25

In a double-blind study of people with diabetic nerve damage (neuropathy), supplementing with acetyl-L-carnitine was significantly more effective than a placebo in improving subjective symptoms of neuropathy and objective measures of nerve function.26 People who received 1,000 mg of acetyl-L-carnitine three times per day tended to fare better than those who received 500 mg three times per day.

In a double-blind study of people with diabetic neuropathy, supplementing with acetyl-L-carnitine was significantly more effective than a placebo in improving subjective symptoms of neuropathy and objective measures of nerve function.27 People who received 1,000 mg of acetyl-L-carnitine three times per day tended to fare better than those who received 500 mg three times per day.

1 Star

Amenorrhea

Refer to label instructions

Acetyl-L-carnitine may help restore menstruation in some amenorrheic women.

Acetyl-L-carnitine is an amino acid that may have effects on brain chemicals and hormones that control female reproductive hormones. In a preliminary trial, 2 grams daily of acetyl-L-carnitine was given to amenorrheic women who had either low or normal blood levels of female hormones. Hormone levels improved in the women with low initial levels, and half of all the women resumed menstruating within three to six months after beginning supplementation.28 Controlled trials are needed to confirm these promising results.

1 Star

Male Infertility

Refer to label instructions

Acetylcarnitine may be a useful for treatment of male infertility caused by low quantities of immobile sperm.

L-carnitine is a substance made in the body and also found in supplements and some foods (such as meat). It appears to be necessary for normal functioning of sperm cells. In preliminary studies, supplementing with 3–4 grams per day for four months helped to normalize sperm motility in men with low sperm quality.29, 30 While the majority of clinical trials have used L-carnitine, one preliminary trial found that acetylcarnitine (4 grams per day) may also prove useful for treatment of male infertility caused by low quantities of immobile sperm.31

How It Works

How to Use It

Most research involving acetyl-L-carnitine has used 500 mg three times per day, though some research has used double this amount.32

Where to Find It

Acetyl-L-carnitine is a molecule that occurs naturally in the brain, liver, and kidney. It is also available as a dietary supplement.

Possible Deficiencies

Acetyl-L-carnitine levels may decrease with advancing age. However, because it is not an essential nutrient, true deficiencies do not occur.

Interactions

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Severe peripheral neuropathy (painful sensations due to nerve damage in the hands and feet) often develops in people taking didanosine or other drugs in its class. People with peripheral neuropathy who were taking one of these drugs were found to be deficient in acetyl-L-carnitine.41 In a preliminary trial, supplementation with 1,500 mg of acetyl-L-carnitine twice a day resulted in improvement in the neuropathy after six months in people taking didanosine or related drugs.42 Similar benefits were seen in another study that used the same amount of acetyl-L-carnitine.43

Severe peripheral neuropathy (painful sensations due to nerve damage in the hands and feet) often develops in people taking stavudine or other drugs in its class. People with peripheral neuropathy who were taking one of these drugs were found to be deficient in acetyl-L-carnitine.58 In a preliminary trial, supplementing with 1,500 mg of acetyl-L-carnitine twice a day resulted in improvement in the neuropathy after six months in people taking stavudine or related drugs.59 Similar benefits were seen in another study that used the same amount of acetyl-L-carnitine.60

Acetyl-L-carnitine in the amount of 1,000 mg three times per day for eight weeks has been shown to improve nerve damage (neuropathy) caused by the chemotherapy drug cisplatin.65

Support Medicine

none

Reduces Effectiveness

none

Potential Negative Interaction

none

Explanation Required

none

The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Side Effects

Side effects from taking acetyl-L-carnitine are uncommon, although skin rash, increased appetite, nausea, vomiting, agitation, and body odor have been reported in people taking acetyl-L-carnitine.66, 67

The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.

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